AP BIOLOGY

Detailed explanation-1: -A polygenic trait is a characteristic, such as height or skin color, that is influenced by two or more genes. Because multiple genes are involved, polygenic traits do not follow the patterns of Mendelian inheritance . Many polygenic traits are also influenced by the environment and are called multifactorial.

Detailed explanation-2: -In humans, height, skin color, hair color, and eye color are examples of polygenic traits. Type-2 diabetes, coronary heart disease, cancer, and arthritis are also deemed polygenic. However, these conditions are not just genetic since polygenes can be influenced by environmental factors.

Detailed explanation-3: -Polygenic traits are traits that are controlled by multiple genes instead of just one. The genes that control them may be located near each other or even on separate chromosomes. Because multiple genes are involved, polygenic traits do not follow Mendel’s pattern of inheritance.

Detailed explanation-4: -In polygenic inheritance, a particular character is controlled by three different genes. In general, phenotypic ratio is 1:6:15:20:15:6:1 instead of 27:9:9:9:3:3:3:1 in second filial generation. Here, the genotype of parents is AaBbCc and AaBbCc. Gametes formed are ABC, ABc, Abc, abc, aBC, aBc, abC, AbC.

Detailed explanation-5: -Traits controlled by a single gene with more than two alleles are called multiple allele traits. An example is ABO blood type. Your blood type refers to which of certain proteins called antigens are found on your red blood cells.